【popular science】 comparison of driving forces of portable hand-held laser leveling machine
Hearing some remarks similar to "the hydraulic press is stronger than the electric leveling machine", misled consumers and felt it necessary to analyze the working principle of the portable hand-held leveling machine, eliminate the false and preserve the true, so as to correct the audio-visual situation.
The hand-held portable leveling machine is a typical two-point one-side support. Two points refer to two tires. One side refers to the contact surface between the vibrating plate and the concrete. Geometry tells us that a stable plane consists of at least three points. Therefore, two points and one side constitute the basic structural model of the portable hand leveling machine, which is stable. In actual construction, there is no need to hold the handle (the safety switch is tied), which is the reason.
The whole fuselage takes the tire shaft as the rotation center, which is similar to the seesaw in a children's paradise. Whichever is heavy, the other will sink. For the machine, the vibrating plate needs to contact the concrete at all times to transmit vibration and play the role of vibration. Therefore, the head part must be heavier than the handle part.
Concrete is fluid and fluid is buoyant. The vibrating plate floats on the concrete surface like a boat. When the gravity applied by the machine head to the vibrating plate is greater than the buoyancy of the vibrating plate by the concrete, the vibrating plate will sink. For a vibrating plate with a certain size and shape, how much it sinks depends on how much the nose is heavier than the tail. Like the draft of a ship, it depends on how much cargo it carries. Overload, the ship will sink. It can be seen that the nose part can not be too heavy. Too heavy, vibration plate will sink too much, thus damaging the concrete surface. If it is too light, the scraper will be pushed up by slight resistance, and the scraper can't get into the concrete, so it can't scrape off the excess concrete.
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A rake made of a piece of wood can't dig a pile of soil, because the density is too small and the weight is too light, so it's difficult to get into the soil; The excavator bucket can easily dig a deep pit on the hard ground because the bucket and excavator are very heavy and can easily press the bucket into the soil. This presents a problem: the machine head is too heavy and will sink into the concrete; Too light, the scraper cannot scrape off the effect of excess concrete.
Therefore, the front and rear weights of the hand-held leveling machine, whether hydraulic or electric, are strictly distributed according to a certain proportion, and the downward actual gravity of the head is basically the same. Like a seesaw, one end is 80kg fat and the other is 60kg thin. Although the total weight is 140kg, the fat one weighs only 20kg more than the thin one.
Although the weight of Shenlong hydraulic leveling machine is nearly 400kg, which is far more than 220kg of Jiezhou LS-300 electric laser leveling machine, the downward gravity of its head is not much different from that of Jiezhou LS-300. During construction, we sometimes see that when the concrete is too dry or the concrete begins to set, the machine cannot be pulled. At this time, the scraper cannot go down, and the vibrating plate is jacked up and separated from the concrete surface.
Even if your engine is very strong, it is meaningless and ineffective for dry and low slump concrete! Because the weight of the machine head is too light, the scraper can't get into the concrete and can't scrape off the excess concrete. Let a strong man dig a ditch with a wooden rake in his hand, but he can't do a thin old man with a iron rake in his hand. Is it strong enough to make you go up? Therefore, it is shameless to show off the engine power of the large leveling machine. Its essence is to deceive consumers.